Stability Comparison Between Microglassification and Lyophilization Using a Monoclonal Antibody

Producing solid-state formulations of biologics remains a daunting task despite the prevalent use of lyophilization and spray drying technologies in the biopharmaceutical industry. The challenges include protein stability (temperature stresses), high capital costs, particle design/controllability, shortened processing times and manufacturing considerations (scalability, yield improvements, aseptic operation, etc.). Thus, scientists/engineers are constantly working to improve existing methodologies and exploring novel dehydration/powder-forming technologies. Microglassification™ is a dehydration technology that uses solvent extraction to rapidly dehydrate protein formulations at ambient temperatures, eliminating the temperature stress experienced by biologics in traditional lyophilization and spray drying methods. The process results in microparticles that are spherical, dense, and chemically stable. In this study, we compared the molecular stability of a monoclonal antibody formulation processed by lyophilization to the same formulation processed using Microglassification™. Both powders were placed on stability for 3 months at 40 °C and 6 months at 25 °C. Both dehydration methods showed similar chemical stability, including percent monomer, charge variants, and antigen binding. These results show that Microglassification™ is viable for the production of stable solid-state monoclonal antibody formulations.

Coating of Primary Powder Particles Improves the Quality of Binder Jetting 3D Printed Oral Solid Products

Binder jetting (BJ) 3D printing is especially suitable for the fabrication of an orodispersible solid dosage form, as it is an efficient way to avoid the use of mechanical forces typical for compaction-based processes. However, one of the existing challenges related to pharmaceutical applications of BJ is the relatively high amount of binder needed in the primary powder to ensure the sufficient mechanical strength of printed products. In this study, a strategy based on pre-processing with a thin layer coating was explored. With this strategy, the matrix particles (lactose monohydrate) of the primary powder for BJ 3D printing were coated with the binder (polyvinylpyrrolidone, PVP). The investigated compositions of the primary powder contained PVP at three levels, namely, 10 %, 15% and 20% (w/w). The primary powder compositions were prepared with or without the coated lactose powder, and they were subsequently 3D BJ printed into oral solid products with paracetamol as a model active drug substance. The presence of coated lactose in the primary powder increased the interparticulate interactions in the BJ 3D printed products. Especially for the composition with a relatively small amount of binder (i.e., 10% and 15% w/w PVP in the primary powder), the use of coated particles significantly improved the resistance to crushing and decreased the disintegration time of printed products. In conclusion, thin layer coating is an effective way to pre-process primary powder particles for BJ 3D printing of oral solid products.

Particles in Biopharmaceutical Formulations, Part 2: An Update on Analytical Techniques and Applications for Therapeutic Proteins, Viruses, Vaccines and Cells

Particles in biopharmaceutical formulations remain a hot topic in drug product development. With new product classes emerging it is crucial to discriminate particulate active pharmaceutical ingredients from particulate impurities. Technical improvements, new analytical developments and emerging tools (e.g., machine learning tools) increase the amount of information generated for particles. For a proper interpretation and judgment of the generated data a thorough understanding of the measurement principle, suitable application fields and potential limitations and pitfalls is required. Our review provides a comprehensive overview of novel particle analysis techniques emerging in the last decade for particulate impurities in therapeutic protein formulations (protein-related, excipient-related and primary packaging material-related), as well as particulate biopharmaceutical formulations (virus particles, virus-like particles, lipid nanoparticles and cell-based medicinal products). In addition, we review the literature on applications, describe specific analytical approaches and illustrate advantages and drawbacks of currently available techniques for particulate biopharmaceutical formulations.

Fluorine (19F) Nuclear Magnetic Resonance Spectroscopy For Real Time Maraviroc Analysis From Microparticulate Systems

Real time analysis of pharmaceuticals in controlled release nano and microsystems remains a challenge. It is hypothesized that fluorine 19 nuclear magnetic resonance (¹⁹F qNMR) can be used for real time quantification and in vitro release of maraviroc (MVC). The release of maraviroc was analyzed in simulated body fluids from spray dried sodium alginate microspheres (MS) using the ¹⁹F qNMR method. Calibration produced a linearity curve in concentration range (0.42 mg/ml - 15 mg/ml), and the limits of detection and quantification values were 0.97 mg/ml and 2.93 mg/ml, respectively. The method was confirmed to be specific, accurate, precise, and robust (%RSE > 2%). MVC was successfully microencapsulated (18% w/w) as evidenced by the FT-IR spectra and SEM images. The MS had an average diameter of 2.522 ± 0.15 μm, with a zeta potential of - 61.31 ± 2.1 mV. Overall, the ¹⁹F qNMR method enabled a direct and real time quantification of MVC for an efficient drug release kinetics. This approach could be potentially used to quantify fluorinated drug potency, purity, and stability, and evaluate in vitro release kinetic from different formulations.

Subvisible Particles in Solutions of Remicade in Intravenous Saline Activate Immune System Pathways in In Vitro Human Cell Systems

Among patients that receive Remicade® therapy, more than 20% have adverse infusion related reactions and approximately 50% have immunogenic responses.^1-3 Upon characterization of initial Remicade®-IV solution we observed a high concentration of subvisible particles that could inadvertently be delivered to patients. This solution was processed through the IV infusion system, mimicking the typical clinical administration setup - either with or without an in-line filter connected to the IV line. The samples generated thereafter were tested using various in vitro assays for activation of the innate immune system via cytokine release in whole blood and in peripheral blood mononuclear cell (PBMC) cultures, and activation of the Toll like receptors (TLRs). Activation of the adaptive immune system was evaluated by monitoring upregulation of surface receptors on dendritic cells (DCs) and CD4+ T cell proliferation in response to IV solution of Remicade®. Our results indicate that subvisible particles in Remicade®-saline solution have a significant role in activation of the immune system but there are extrinsic factors potentially contributed by the in-line filters or other process parameters that also contribute to immune system activation.

Poly(δ-valerolactone-co-allyl-δ-valerolactone) cross-linked microparticles: Formulation, characterization and biocompatibility

A novel polymeric material, poly(δ-valerolactone-co-allyl-δ-valerolactone) (PVL-co-PAVL), was used to manufacture microparticles (MPs) for sustained drug delivery. PVL-co-PAVL MPs were formulated using a modified oil-in-water approach, followed by a UV-initiated cross-linking process. Prepared MPs had a smooth spherical morphology and cross-linking of the copolymer was found to improve the integrity and thermal stability of the MPs. Paclitaxel (PTX) was successfully loaded into the MPs at a high drug loading capacity, using a post-loading swelling-equilibrium method. In vitro evaluation showed that the PVL-co-PAVL MPs provide sustained release of PTX, which exhibited first-order release kinetics. A subsequent pilot pharmacokinetic study was carried out on the PTX-loaded PVL-co-PAVL MPs. During this study, serum levels of PTX were monitored following subcutaneous administration of the MPs to Sprague-Dawley rats. Overall, the in vivo release of PTX from the MPs was lower than expected based on the in vitro release studies. Detectable serum levels of PTX suggest that sustained release of drug was achieved in vivo. Minimal changes in subcutaneous tissue were observed at the site of injection. Future studies will further examine the localized and systemic distribution of drug following administration in this new polymer-based MP system.

Affinity-Based Polymers Provide Long-Term Immunotherapeutic Drug Delivery Across Particle Size Ranges Optimal for Macrophage Targeting

Drug delivery to specific arms of the immune system can be technically challenging to provide prolonged drug release while limiting off-target toxicity given the limitations of current drug delivery systems. In this work, we test the design of a cyclodextrin (CD) polymer platform to extend immunomodulatory drug delivery via affinity interactions for sustained release at multiple size scales. The parameter space of synthesis variables influencing particle nucleation and growth (pre-incubation time and stirring speed) and post-synthesis grinding effects on resulting particle diameter were characterized. We demonstrate that polymerized CD forms exhibit size-independent release profiles of the small molecule drug lenalidomide (LND) and can provide improved drug delivery profiles versus macro-scale CD polymer disks in part due to increased loading efficiency. CD polymer microparticles and smaller, ground particles demonstrated no significant cytotoxicity as compared to the base CD monomer when co-incubated with fibroblasts. Uptake of ground CD particles was significantly higher following incubation with RAW 264.7 macrophages in culture over standard CD microparticles. Thus, the affinity/structure properties afforded by polymerized CD allow particle size to be modified to affect cellular uptake profiles independently of drug release rate for applications in cell-targeted drug delivery.

Applying Pattern Recognition as a Robust Approach for Silicone Oil Droplet Identification in Flow-Microscopy Images of Protein Formulations

Discrimination between potentially immunogenic protein aggregates and harmless pharmaceutical components, like silicone oil, is critical for drug development. Flow imaging techniques allow to measure and, in principle, classify subvisible particles in protein therapeutics. However, automated approaches for silicone oil discrimination are still lacking robustness in terms of accuracy and transferability. In this work, we present an image-based filter that can reliably identify silicone oil particles in protein therapeutics across a wide range of parenteral products. A two-step classification approach is designed for automated silicone oil droplet discrimination, based on particle images generated with a flow imaging instrument. Distinct from previously published methods, our novel image-based filter is trained using silicone oil droplet images only and is, thus, independent of the type of protein samples imaged. Benchmarked against alternative approaches, the proposed filter showed best overall performance in categorizing silicone oil and non-oil particles taken from a variety of protein solutions. Excellent accuracy was observed particularly for higher resolution images. The image-based filter can successfully distinguish silicone oil particles with high accuracy in protein solutions not used for creating the filter, showcasing its high transferability and potential for wide applicability in biopharmaceutical studies.

Characterization of Brain-Targeted Drug Delivery Enhanced by a Combination of Lipid-Based Microbubbles and Non-Focused Ultrasound

The combination of focused ultrasound (FUS) and microbubbles, an ultrasound (US) contrast agent, has attracted much attention for its ability to open the blood brain barrier (BBB) and deliver drugs to the brain parenchyma. FUS can concentrate US energy in a restricted space, whereas non-focused US can affect a wide area of tissue. Non-focused US is also promising for drug delivery to the brain and other tissues. We have previously developed lipid-based microbubbles (LBs), and demonstrated that non-focused US and LBs have potential for drug delivery to tumor tissues. In this study, to achieve efficient and safe brain-targeted drug delivery, we evaluated the characteristics of BBB opening using non-focused US and LBs. Our results indicated that LBs could induce BBB opening with non-focused US. US frequency and intensity affected the efficiency of BBB opening and brain damage, and showed that the dose of LBs was also related to the efficiency of BBB opening. Furthermore, the combination of non-focused US and LBs could deliver macromolecules at 2000 kDa to the brain, and the induction of BBB opening was found to be reversible. These results suggest that the combination of non-focused US and LBs has potential as a brain-targeted drug delivery system.